Process of rendering oleaginous tissue material



Fatented Doe. I,

PROCESS OF RENDERING OLEAGINOUS TISSUE MATERIAL Louis B. Libby, Bolton, and Lloyd F. Henderson,

Reading, Mass alaignors to Lever Brothers Company, Cambridge, Mass a corporation of Maine No Drawing Application April 26, 1845, erial No. 590,526

ir. Claims. (or zso-mm This invention relates to the processing of oleaginous materials in order to recover oleaginous products therefrom, and more particularly to a process of rendering oleaginous tissue material to obtain fatty glyceride which have good color. and good stability against auto-oxidation and the development of odors and colors.

In general, rendering processes are conducted in either open vessels or closed vessels. The former may be open to the oxygen in the atmosphere and the latter may be protected therefrom. The processes also may be considered as of the wet type or of the dry type. In the wet type of rendering process, the rendering stock is heated or contacted with live steam. In the dry type of rendering process, the operation is carried out under conditions such that most of the moisture present in the stock being treated is reni'oved. Many methods have been proposed heretofore for subsequently purifying. bleaching, or th 'rwise improving the products obtained by the usua rendering processes. These include treatment with -various active reagents including acids. bases'and salts. All of these refining or after-treatments have the economic drawback of adding to the cost of the process'and leaving much to be desired in the final product.

Despite these numerious proposals. a large portion of commercial conventionally rendered tallow. and other fats and oils is of poor color; they deteriorate rapidly'into products of still poorer color and odor. It has been necessary for the users of fats to develop satisfactory processes for refining and bleaching lower grade stocks, or other processes of treating them so as to make themusable. i

In sharp contrast to the heretofore known rendering processes and the resort to extensive bleaching of the rendered oils or fats to improve their color and other properties after renderin it has now been discovered that rendered products having markedly improved color, odor, and

stability against auto-oxidation may be obtained directly by an improved rendering process. More particularly the fatty tissue is rendered in the presence of a relatively small amount of a finely dispersed agent supplying hydrated silica to the mass being rendered. i. e., containing free hydratedsilica or a material which yields it under in a small amount andare relatively inexpensive; their use does not necessitate costly changes in rendering processes as usually practiced. Accordingly, the improved products are obtained at little or no additional cost. The improved products obtained in accordance with the invention are such as would command a higher market price than the unimproved fatty material; and also the need for subsequent bleaching thereof is either eliminated or reduced. They can be stored with less deterioration and used in the manufacture of higher grade soaps and other products.

It is an object of the present invention to provide an improved method for processing oleaginous materials.

It is another object of the invention to provide an economical and low cost process for rendering relatively low grade fat containing tissues or oleaginous materials to obtain relatively high grade oleaginous products such as glyceride fats and o s.

It is still another object of the invention to provide a process for rendering which may be carried out in the usual type rendering apparatus and following the established procedural techniques.

. Other objects of the invention will be apparcut as it is more fully disclosed hereinafter. These objects are achieved,in general, as follows:

39 In accordance with the invention, oleaginous stock or fatty tissue is rendered in the presence 01' silicic acid or any other agent containing or capable of ifurnishing hydrated silica to the mass and also capable of being finely dispersed therein.

as Usually about 0.1%to about 5.0% of the added the nature of the tissue to be rendered and the purpose for which the fat is to be used. The added agent is not dissolved in or carried over in the tallow or rendered oleaginous material product in appreciable amounts. For many purposes,

the products 'obtained are directly usable.

The materials which may be added in accordance with the invention may be illustrated by hydrated silica. such as silicic acids or silica gel or hydrated amorphous silica 0r metasilicic acid.

the rendering conditions. Such agents are used 59 Other materials which comprise or supply hydrated silica include ethyl silicate. tale. (a natural acid magnesium silicate), feldspar (a natural aluminum silicate rock which also usually contains at least one of the group potassium, sodium, calcium, barium. lithium and rubidium) and kaolin (a material resulting from the weathering of feldspar). Silica gel is a colloidal silicic acid or hydrated silica. All of these materials are characteried by their containing or being capable of furnishing hydrated silica in or to the mass being rendered under the rendering conditions. If the hydrated silica supplying agent has a saponifyingaction, it may be necessary to include an acidic material to suppress this action. Thus the process can be carried out under conditions in which there is no substantial saponiflcation of oleaginous material or product.

In the standard rendering processes,-the various grades of low grade stocksv are generally treated separately and often treated diflerently. The primary tallows are prepared from suet trimmings, cord and kosher trimmings. Generally a yield of about 50% to 70% of the charge is obtained. Lower grade materials are obtained from inferior stocks such as bones, oifal, and various scraps and waste fats from restaurants, household cooking grease, or from butcher shops. The yield of tallow from the bones and oflal is about 20% of the weight of the charge. The oleaginous material which may be treated in accordance with the invention includes, among others, any of the foregoing types as well as vegetable and marine animal or fish types. In the recovery of fat from the latter types, the hydrated silica supplyin agent ma be added to the ground I vegetable meats or marine animal meat in the cooking step, wherein the meats are conditioned for removal of the fat by a screw or hydraulic press or expeller. An improved .fatty product will be obtained thereby.

The procedural operations do not vary from those employed in known rendering processes.

For economic reasons the time of treatment and temperature used are generally the minimum required to remove the fat from the tissue. The fat may be removed at the end of the rendering or continuously, as is well known. The hydrated silica supplying agent may be mixed with the tissue before the heating is started if desired, or

during the heating, and it may be added stepwise in one or more batches during the rendering.

Although the invention is not limited to any theory or explanation of the mode of operation or the results obtained, and no theory is claimed as such, it is thought that the following may be of aid in morefully understanding the invention.

The stocks to be rendered contain various color and color forming bodies. The presence of the hydrated silica agent is thought to prevent the dispersion of such bodies in the rendered fat. The

.stocks contain materials which are highly susceptible to auto-oxidation, and if these materials are carried into the fat, this property is also present in the rendered oleaginous product. The presence of the hydrated silica agent seems to destroy these bodies or prevent their removal with the fat and thereby prevents or represses auto-oxidation in the rendered material.

The following examples are given as illustrative but in no wise as limitations of the invention as otherwise disclosed herein. The materials of these examples were tested for deterioration by determining the amount of peroxides therein. They were tested for color in accordance with the official methods of the American Oil Chemists Society using the standard Lovibond color glasses.

Example 1 A charge of beef trimmings was heated in an open vessel at 115 C. for hours with agitation. The rendered fat was decanted from the residue tissue remaining in the vessel, and its color and peroxide number were determined.

Similar charges of similar trimmings were mixed with 1% (by weight) of a hydrated silica supplying agent, and heated at 115 C. for hours in a similar vessel with agitation. The procedure was identical except for the presence of the hydrated silica supplying agent in the mixture. The rendered fat was decanted and similarly tested for color and peroxide number.

The results of these tests follow:

Rendered Fat Added agent Color (5%" Column) Peroxide N 0.

Red Yellow Blue None l.

Talc Amorphous Silica (Wet Ground).

Example 2 (A) A charge of raw stock trimmingswas heated in an open vessel to 125 'C. with agitation for two hours. The rendered fat was decanted from the residual tissue or cracklings and tested for color, odor and peroxide number.

(B) The same procedure was followed except thatthe trimmings contained 1% (by weight) of metasilicic acid, 1. e., they were heated with the metasilicic acid to a temperature of 125 C. for two hours with agitation. The rendered fat was decanted and tested for color, odor and peroxide number.

The results of these tests follow:

Color of Rendered Fat 4.0Red,50.0 Yel- 0.9Red,9.0Yellow.

(5%" column). low. Peroxide No. of Rendered 22.5 0.2.

get alter standing one ay. 8o Odor of Rendered Fat Poor Good.

aim! standing over night.

These results clearly show a very marked improvement,.obtainable by rendering in the. presence of 1% of metas ilicic acid.

Example 3 mixture. The rendered fat was decanted and tested. as above.

The results of these tests follow:

Color oi Rendered r: as Red, 76.0 Yel- 0.6 Red, 6.0 Yel- (5 a" column). low, 4.0 Blue. low, 0.0 Blue. Pero do No. oi Rendered 42.9 16.05.

Fat aiter standing one 'Y- l Odor oi Rendered Fat Poor Good. liter standing over night.

Example 4 (A) A mixture of equal weights of bone and suet was heated at 140 C. for 1% hours with agitation. The rendered fat was decanted from the residue tissue. Part of this product was tested for color, and another part was bleached with 6% (by weight) of activated earth and the bleached product tested for color.

(8) A similar mixture of equal weights of bone and suet but containing 1% (by weight) of metasilicio acid and 1% (by weight) of silica gel was heated at 140 C. for 1 hours with agitation. The rendered fat was decanted and a part of this tested for color, and anotherpart bleached with 6.0% (by weight) of activated earth and the bleached product tested for color.

The results of these tests follow: 3

Color of Rendered Fat 12.0 Red, 76.0 2.0 Red, 20.0

' Yellow (1" column). Yellow. Color of Bleached Rend- 2.0 Red, 21.0 0.1 Red, 1.0 Yelcred Fat (1 column). Yellow. low.

This example demonstrates the susceptibility of the tallow, rendered in accordance with the. invention, to bleaching action. It would be difllcult, if not impossible, to have bleached the ordinary rendered tallow to a color of 0.1 red and 1.0 yellow.

Example 5 dered fat was decanted. It tested 0.6 red in a 5%" column.

This example illustrates the marked diflerence between rendering in the presence of silica gel and the treatment of rendered fat with silica gel. It also shows that silica gel is not an efficient bleaching agent as compared with the known bleaching qualities of activated earths.

Example 6 A mixture or oleaainous rendering stool: was made up of equal parts by .weight of suet trimmines and cord flat. Equal parts of this mixture containing difl'erent hydrated silica supplying agents were heated at 125 C. with agitation for hour. The rendered tat was decanted and tested for color and odor.

The results of these tests i'ollow:

None 6.0 Red, 75.0 Yellow. Poor. 1 weight percent ethyl sili- 2.4 Red,50.0 Yellow. Excellent.

ca 1 weiight percent metasilicic 2.6 Red, 50.0 Yellow. 000d.

ac 0.6 weight percent metasi- 2.6 Red, 50.0 Yellow. Do.

licio acid.

The data of this example show that even very small amounts of metasilicic acid may be used to advantage and also that an organic silicate such as ethyl silicate is a particularly efllcient agent for use in accordance with the invention.

Example 7 Using a, rendering stock similar to that of the preceding example, 10 lb. portions containing various added agents were heated at 120 C. with agitation for minutes in an iron apparatus. The rendered fat was separated from the cracklings or residue tissue by filtering through a stainless steel screen. In some of the runs, a, part of the rendered fat was tested for color, another part was converted to its soap, the soap bleached with 0.2 weight per cent of commercial sodium hydrosulfite and then converted into the free fatty acids; another part was bleached with'a commercial activated earth. A part of this bleached tallow was tested for color, and another part thereof converted into its soap, washed and bleached with 0.2% sodium hydrosulfite and then converted into the free fatty acids. The free fatty acids were testedtor color. The ethyl silicate and silica'gel rendered products were tested for color only.

The results of these tests follow:

' 1 Wei ht 0.5 Weight 1.0 Weight 1.0 Wei he Added Agent None Percent eta- Percent Meta- Percent Silica Percent li thyl sillcic Acid sllicic Acid Gel Silicate Color of freshly Rendered Fat (6% Column) 5-5 R, 76.0 Y, 4.7 R, 50.0 Y, 5.8 R, 75.0 Y, 6.0 R 75.0 Y, 6 4 R 500 Y,

3.0 B. 0.75 B. 0.9 B. 0.0 is. .o is. (b2152 Flatty .;.cids ircm Soap from freshly Rendered Fat 4.8 R, 50 0 Y... 2.7 R, 27.0 Y-.- 3.0 R, 35.0 Y...

co umn Bleached Rendered Fats:

Amount of bleaching agent used in weight percent 6.0 3.0 4.0 Color (5% column) ,0-5 R, 5.0Y.... 0.5 R,6OY 0.4 R, 4.0Y Color oi Fatty Acids from Bleached Rendered Fat (5%" 2.5 R, 25.0 Y... 1.2 R, 13 0 1.5 R, 15.0 Y--.

column).

red in a 5%" column, showing that the silica gel did not exert, a bleaching action on the tallow.

(B) The same amount of suit in admixture with 2.0% (by weight) of silica gel was heated at 120 C. with agitation for one hour. The ren- These results show that rendering in the presence of a hydrated silica supplying agent gives a fat of improved color and that corresponding .bleached products can be obtained therefrom by only about half of the bleaching agent required cassava for the fat from ordinary rendering processes.

They also show that soaps made from such products yield lighter colored fatty acids.

Example 8 ether, the extract phase filtered through coarse filter paper, and the ether evaporated from the filtrate. The fresh tallow. bleached tallow, and oil from the crackings were tested for color.

(B) A similar run and series of tests were made using 1 weight per cent of metasilicic acid in the rendering stock.

The results of these tests follow:

Color of freshly Rendered Fat 80.5 R, 76.0 37.5 R. 75.0 Y,

(5% column). Y, 3.0 B. 1.45 B. g" column) 10.0 R, 75.0 Y 4 7 R, 50.0 Y. olor of bleached Rendered Fat 80 R, 50.0 Y- 3 5 R, 36.0 Y

5%" column). or of oil from cracklings (1 l6 R, 76 0 Y 60R,75.0Y

column).

These data show that the presence of a hydrated silica supplying agent in even low grade rendering stocks gives a very much improved product and that bleached products obtained therefrom are much better than those from ordinary rendering processes. They also indicate that the agent acts to set or destroy the color in the residue. so that it is not carried-over into fat or oil extracted therefrom by solvent extraction processes. This is a very important economic advantage of the new process.

It is appreciated that it has been proposed heretofore to render fat in the presence of activated carbon by methods which protect the stock from oxygen of the atmosphere when it is at the high temperatures used in rendering. The hydrated silica supplying substances used in accordance with the invention are not the equivalents of activated carbon, since the-hydrated silica supplying substances are eificient in rendering in the presence of air. This is a marked advantage in a commercial operation.

By rendering is meant heating to a temperature above room temperature which facilitates the removalof the oil or fat fromthe tissue while maintained at said temperature, or in a later removing operation which may or may not be carried out at said temperature and which may or may not include mechanical expression of the oil or fat from the tissue.

In view of the foregoing disclosures, it will be apparent to one skilled in the art that this process may be applied to stocks equivalent to those mentioned, using equivalent hydrated silica supplying agents, in accordance with the invention. The invention contemplates all modifications within the scope of the appended claims.

We claim:

1. A method which comprises rendering oleaginous tissue material by heating it toa temperature which facilitates removal of fatty glyceride therefrom, in'the presence of a small proportion of a substance supplying finely dispersed bydrated silica thereto, and separating the rendered fatty glyceride therefrom.

2. A method which comprises rendering oleaginous tissue material by heating it to a temperature which facilitates removal of fatty glyceride therefrom, in the presence of oxygen and a small proportion of a substance supplying finely dispersed hydrated silica thereto. and separating the rendered fatty glyceride therefrom.

3. A method which comprises rendering oleaginous tissue material by heating it to a temperature which facilitates removal of fatty glyceride therefrom, in the presence of a small proportion of a finely dispersed hydrated silica containing substance, and separating the rendered fatty glyceride therefrom.

4. A method which comprises rendering oleaginous tissue material by heating it to a temperature which facilitates removal of fatty glyceride therefrom, in the presence of a'small proportion of a finely dispersed hydrated silica, and separating the rendered fatty glyceride therefrom.

5. A method which comprises rendering oleaginous tissue material by heating it to a temperature which facilitates removal of fatty glyceride therefrom, in the presence of a small proportion of a finely dispersed talc, and separating the rendered fatty glyceride therefrom.

6. A method which comprises rendering oleaginous tissue material byheating it to atemperature which facilitates removal 01 fatty glyceride therefrom, in the presence of a small proportion of a finely dispersed feldspar, and separating the rendered fatty glyceride therefrom. v

7. A method which comprises mixing oleaginous tissue material with about 0.1% to about 5.0% of a substance supplying finely dispersed hydrated silica thereto, based on the weight of the total mass, rendering the tissue by heating to a temperature which facilitates removal of fatty glyceride therefrom, and separating the rendered fatty glyceride therefrom.

8. A method which comprises mixing oleaginous tissue material with about 0.1% to about 5.0% of a finely dispersed hydrated silica containing substance, based on the weight of the total mass, rendering the tissue by heating to a temperature which facilitates removal of fatty glyceride therefrom, and separating the rendered fatty glyceride therefrom.

9. A method which comprises mixing oleaginous tissue material with about 0.1% to about 5.0% of a finely dispersed hydrated silica, based on the weight of the total mass, rendering the tissue by heating to a temperature which facilitates removal of fatty glyceride therefrom. and separating the rendered fatty glyceride therefrom.

10. A method which comprises mixing oleaginous tissue material with about 0.1% to about 5.0% of a finely dispersed talc, based on the weight of the total mass, rendering the tissue by heating to a temperature which facilitates removal of fatty glyceride therefrom, and separating the rendered fatty glyceride therefrom.

11. A method which comprises mixing oleaginous tissue material with about 0.1% to about 5.0% of a finely dispersed feldspar, based on the weight of the total mass, rendering the tissue by heating to a temperature which facilitates removal of fatty glyceride therefrom, and separat- Number ing the rendered fatty glyceride therefrom. 1,959,346 LOUIS H. LIBBY. 1,973,790 LLOYD F. HENDERSON. 1.992.979

t 5 REFERENCES CITED The following references are of record in the gg g flle of this patent: J

UNITED STATES PATENTS 10 Number Name Date 11,615 Melssl June 29, 189':

Name Date Cummins May 22, 1934 Appleton Sept. 18, 1934 Wollner Mar. 5, 1935 FOREIGN PATENTS Country Date France June 23, 1906 

